The major goal of the Physiology Core of the Scripps NeuroAIDS Preclinical Studies (SNAPS), CSPAR, is to continue to provide neurophysiological assessment of AIDS-related functional pathology using a variety of established and new animal models with clinical phenotypes relevant for neuroAIDS. The Core services will include continued evaluation of current primate and feline models infected with the analogous lentivirus (SIV and FIV, respectively) as well as assessment of existing and new mouse models representing molecularly engineered phenotypes relevant for HIV-1 infection. The Core will provide a broad spectrum of analyses for the detection of functional disease progression and identification of underlying mechanisms. In addition, the Core will work to recruit new SNAPS collaborators who will further enrich the assessment potential of the Core and its contribution to the neuroAIDS field. The Core is organized into two interacting units that carry out specific scientific analyses. The analyses provide sensitive measures of disease progression, functional deficits and underlying mechanisms. The in vivo analysis unit will carry out studies in mouse, primate and feline models of NeuroAIDS utilizing in vivo techniques including extracellular single unit electrophysiological recording, sensory potential recording and radio telemetry. The in vitro analysis unit will use electrophysiological recordings of brain slices from animal models of NeuroAIDS or cultures prepared from these models. The in vitro unit will also carry out studies of these models using live cell measurement of cytosolic calcium levels and anatomical studies of receptor expression and localization. Important strengths of this SNAPS Core include the expertise and knowledge of the faculty and staff, their long-term working relationships, and their commitment to neuroAIDS research.